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Signing excel apps via a digital certificate can help guarantee that no one has tampered with the code and that what you are executing is what was originally written by the original signer. Further, it helps lock down your security policy. By only running signed code and only importing certificates from people you trust, you can prevent a situation where an an excel document can hijack your whole computer (because it can)

If you rely on VBA solutions within your organization, make sure you sign and then import certificates for all projects.

Sign with Certificate

When creating a VBA project that uses Macros, you can easily sign the project with a self signed certificate using the following steps:

If you don’t already have one, you’ll need to create a self-signed certificate on your computer. If you do have one, you can skip to step 3. If not, go to the Start Menu > All Programs > Microsoft Office > Microsoft Office Tools > and open Digital Certificate for VBA Projects

Enter a name for your certificate and Click OK

Open up your VBA project in Excel, Word, Outlook (etc) and hit Alt + F11 to open up the VBA Project and go to Tools > Digital Signature

On the Digital Signature Menu, Click “Choose”

You should see the Certificate we just created. Select that and hit OK

LINQ to objects will work on any object that implements IEnumerable (the same interface that allows an object to be used in a For Each loop). Datasets are objects, but they don’t implement IEnumerable by default, so you’ll need to first add a reference to a library that adds some extension methods that wrap DataTable and allow it to be enumerated.

This gives you access to each item that is part of the B collection in the same way that a for loop does

ForEach a In b

For the rest of the for loop (or linq query), you can just refer to a and it’s automatically populated as it iterates over the collection.

If you want to loop over a DataTable, you need to create an enumerable table by calling DataTable.AsEnumerable() in order to convert the collection of rows into one that is, well, enumerable. When you loop over a DataTable, you’ll be holding a row object, so you can generally query it in the same way that you otherwise would

The syntax on the bottom just creates a new anonymous object and then selects it. We can Select any object available from the query (i.e. person) or we can create our own on the fly and select that

If you’re unfamiliar with anonymous objects, the syntax may look unfamiliar, but it’s a pretty basic concept. One rarely used feature you might not know about is that if we want to initialize a Person class (which has a Name Property), we can set the name property directly from the initializer using a With {} statement like this:

Dim typedPerson = New Person With {
.Name = "Angelic"
}

If we don’t have a Person class to stuff our data in, or we just want to do it on the fly, we can do the same thing by omitting the class name and then just passing in any properties we want our new class to have.

Note: The compiler will actually create a class for you behind the scenes that has all the properties you’ve specified, but we don’t have a name for it - thus it’s anonymous.

'Anonymous PersonDim anonPerson = NewWith {
.Name = "Angelic"
}

Now we have a query that, once evaluated, will return the joined tables into an enumerable collection of anonymous objects. If we want to convert that back into a new Datatable it’s as simple as calling CopyToDataTable on the query result:

Dim newTable = query.CopyToDataTable()

However, when you do this right now, you’ll get the following error:

CopyToDataTable is not a member of System.Collections.Generic.IEnumerable(Of <anonymous type>)